99% Throttle pulls harder than 100% WOT

[mcsvt]

I am noticing a similar issue. Pulls like a freight train at partial, but falls off at WOT.

Great topic keep up the ideas

[scott_s]

Is there a reason and if so what, as to why not make the WOT advance table similiar to the Part throttle advance table?

[WowZer]

fwiw - my mini was the same way. leaned out the wot table in d-cal slightly at the higher rpms (monitored knock and a/f just in case). runs perfect now. who wants only 99% throttle!!!

[william]

This whole problem is super common. The why has been covered, but the "fix" issue is a bit dicey. If you are able to adjust your WOT table to be a bit leaner, and you can monitor engine parameters, you are going to get free power. If you can't, and you simply up your boost for example, ala MBC, you may eventually reach a point where the WOT blahs are gone, but by doing so, you are now in dangerous territory at part throttle. Part throttle meaning any TPS voltage that triggers the cal to respond to the O2 input. I have been through this, and I am one of the many who learned the hard way that part throttle romps can end your pistons in a hurry.

[puppet]

william ... I'm not sure I understand how tweaking the WOT table would effect the part throttle tables? Is it because they are adaptive?

A friend tells me that as the weather changes here, this issue should be less noticable. I have since pulled a few more pounds of fuel out. The throttle tip in has improved a good bit. Still a bit fat on both ends though. Don't get me wrong ... the engine runs good. ... *just that last little step.


*Famous TD last words.

[Canty]

Throttle Tip??? What is that. And...we are all having problems but no one seems to give a clear answer. Are you all who has had this problem and fixed it saying that all we need to do is to adjust our fuel to be richer/leaner at WOT. Wont that affect the rest of the throttle positions. Or due to the O2 sensor doing its thing a slight adjustment to make WOT work wont affect the rest of the peddle position?
Matt

[Shel-Game]

It's not a "problem" at all. Stock, these cars didn't allow full boost until WOT. That way, full power was only at WOT. WOT A/F was designed to be safe (~12:1). At part throttle, driveability and emissions are more important. So, they used the O2 feedback to try to maintain a 14.7:1 A/F. If you run 14.7:1 at full boost, you will eventually melt down the pistons.

If you wanted to, you could adjust the WOT table to give you close to 14.7:1 A/F. Heck, why not go even higher. That would make even more power, for a short time. It would also give you the benefit of a self lightening car (as the pistons go out the tailpipe).

I'm not really trying to be a smart@ss, but it's a well documented bad idea to run under boost at A/F ratios higher than 12:1 or so. I'm pretty sure it's on the dodgegarage, too, if you don't believe me...

[william]

Quote:

Originally Posted by puppet william ... I'm not sure I understand how tweaking the WOT table would effect the part throttle tables? Is it because they are adaptive? A friend tells me that as the weather changes here, this issue should be less noticable. I have since pulled a few more pounds of fuel out. The throttle tip in has improved a good bit. Still a bit fat on both ends though. Don't get me wrong ... the engine runs good. ... *just that last little step. *Famous TD last words.

Puppet, I was just meaning that if you set your engine to run "lean" (maximum performance, say greater than 12:1) at WOT by adding more boost, your engine will be dangerously lean when running at part throttle. If your computer controls the boost this becomes somewhat less of an issue due to less agressive spoolup. If you adjust your WOT by adjusting the cal itself, you can lean it out at WOT without affecting part throttle safety.